Within
the Datamath Calculator Museum you'll notice a lot of credit card sized
calculators like the TI-1754, TI-1780,
TI-1786, TI-307,
Canon LC-7, Casio LC-79, or Toshiba LC-851.
All these calculators have two dimensions common: The length and the width. But
we never talked about the third dimension, the height or thickness of the
calculators.

The Casio FILM CARD SL-800 is the only real credit card
sized calculator and matches exactly the ISO 7810 standard. This standard is
valid for all credit and debit cards and defines a size of 85mm x 54mm x 0.8mm (3.375"
x 2.175" x 0.030").

Squeezing a calculator in such a thin housing is not
the easiest job and some limitations are obvious:

• Be sure not to damage
the unit by bending or dropping. For example, do not carry it in your
hip pocket.• If any part of the display or its reverse
side is touched, it will momentarily discolor, however, this
is not a malfunction but results from the unit's super thinness. Special
care should be taken not to excessive pressure the display or
push it with a pointed object in order to prevent malfunctions. • Note that the unit has small indentations
which are a necessary part of the production process. • Since the unit is composed of precision
electronic parts, never attempt to take it apart.